Disclosed is a method for preparing a resistant dextrin product by using compound enzyme treatment. Starch is first subjected to high-temperature acidolysis to obtain pyrodextrin which is used as the substrate for the enzyme treatment. A compound enzyme reaction system including a starch branching enzyme and a CGTase is used for preparing the resistant dextrin product. The starch branching enzyme and the CGTase are added simultaneously or sequentially to treat the pyrodextrin to further increase the content of the resistant component in the product. The content of the resistant component of the enzyme treated product reaches up to 65.3%, a 21.3% increase from that of the pyrodextrin before the enzyme treatment.

The present invention relates to preparation and application of a cyclodextrin glucosyltransferase mutant, belonging to the fields of gene engineering and enzyme engineering. By mutating amino acids of cyclodextrin glucosyltransferase, the enzyme activity of the obtained mutant can reach 2.5 times that of wild enzyme. In addition, the cyclodextrin glucosyltransferase mutant obtained in the present invention is simple in purification and suitable for industrial production.

The present invention discloses a method for preparing glucosyl steviol glycosides through enzymatic catalysis under programming temperatures in high throughput, belonging to the technical field of biosynthesis of sweeteners. By using cyclodextrin glucosyltransferase from Geobacillus sp. as a catalyst, steviol glycosides as the glycosyl receptor and dextrin or oligosaccharide as the glycosyl donor, taking a calcium/barium ion salt bridge as the main stabilizer and combining with glycerol to adjust the conformation and binding domain openness of the enzyme, and utilizing transglucosylation and hydrolytic activities of amylase at variable temperatures in different stages, thereby preparing the glucosyl steviol glycosides through enzymatic catalysis under programming temperatures in high throughput. The technology of the present invention can improve the utilization rate of the enzyme, and obtain glucosyl steviol glycosides with good sweetness and good taste.

The disclosure discloses a cyclodextrin glycosyltransferase with enhanced solvent tolerance and preparation thereof, belonging to the technical fields of enzyme engineering and genetic engineering. The disclosure constructs four cyclodextrin glycosyltransferase mutants with enhanced organic solvent tolerance. Among them, the mutant with the optimal tolerance to DMSO and methanol is G539I/R146F/D147N, which is 1.6 times and 1.7 times higher than that of WT, respectively; the mutant with the optimal tolerance to ethanol is R146F, which is 1.4 times higher than that of WT; the mutant with the optimal tolerance to acetone is G539I/R146F, which is 1.5 times higher than that of WT. The disclosure helps to expand the application of glycosyltransferases in organic reaction systems, improves the enzymatic efficiency of CGTase on natural hydrophobic substrates, and has great application prospects.

Provided herein include methods of making mogroside compounds, e.g., Compound 1, compositions (for example, host cells) for making mogroside compounds, and the mogroside compounds made by the methods and compositions disclosed herein, compositions made by the methods (for example, cell lysates), and recombinant cells comprising the mogroside compounds (e.g., Compound 1).

A process for enabling the production of a particulate composition containing crystalline trehalose dihydrate is provided. Including allowing an -glycosyltrehalose-forming enzyme to act on liquefied starch derived from a microorganism of the genus Arthrobacter and a trehalose-releasing enzyme derived from a microorganism of the genus Arthrobacter along with a starch debranching enzyme and a cyclomaltodextrin glucanotransferase; allowing glucoamylase to act on the resulting mixture to obtain a saccharide solution containing ,-trehalose; precipitating crystalline ,-trehalose dihydrate from the above saccharide solution; collecting the precipitated crystalline ,-trehalose dihydrate by a centrifuge; and ageing and drying the collected crystals. Cyclomaltodextrin glucanotransferase derived from a microorganism of the genus Paenibacillus or a mutant enzyme thereof is used to increase the ,-trehalose content in the saccharide solution to over 86.0% by weight, on a dry solid basis, without passing through a fractionation step by column chromatography.

The present invention discloses a conjugate comprising an antigen (for example a saccharide antigen) covalently linked to a Pseudomonas aeruginosa PcrV carrier protein comprising an amino acid sequence which is at least 80% identical to the sequence of SEQ ID NO:1-4, wherein the antigen is linked (either directly or through a linker) to an amino acid residue of the P. aeruginosa PcrV carrier protein. The invention also discloses Pseudomonas aeruginosa PcrV proteins that contain glycosylation site consensus sequences.

A novel protocol is presented for the production of resistant-isomalto-oligosaccharides (IMO-R) that are resistant to human gut enzymes, in particular, dextranase, ?-glucosidase and stomach and pancreatic ?-amylases, thus exhibiting an increasing dietary Fiber effect.

A process for enabling the production of a particulate composition containing crystalline trehalose dihydrate is provided. Including allowing an -glycosyltrehalose-forming enzyme to act on liquefied starch derived from a microorganism of the genus Arthrobacter and a trehalose-releasing enzyme derived from a microorganism of the genus Arthrobacter along with a starch debranching enzyme and a cyclomaltodextrin glucanotransferase; allowing glucoamylase to act on the resulting mixture to obtain a saccharide solution containing ,-trehalose; precipitating crystalline ,-trehalose dihydrate from the above saccharide solution; collecting the precipitated crystalline ,-trehalose dihydrate by a centrifuge; and ageing and drying the collected crystals. Cyclomaltodextrin glucanotransferase derived from a microorganism of the genus Paenibacillus or a mutant enzyme thereof is used to increase the ,-trehalose content in the saccharide solution to over 86.0% by weight, on a dry solid basis, without passing through a fractionation step by column chromatography.

Lipase enzymes and methods of using the lipases in a baking for improving the volume, stability, tolerance of a baked product and/or reducing and reducing or eliminating the use of DATEM.